Solidification matrix including a salt of a straight chain saturated mono-, di-, or tri- carboxylic acid

ABSTRACT

A solidification matrix includes a straight chain saturated carboxylic acid salt, sodium carbonate, and water. The straight chain saturated carboxylic acid salt is selected from a salt of a mono-, di-, or tri-carboxylic acid. The solidification matrix may be used, for example, in a solid detergent composition.

BACKGROUND

The present invention relates generally to the field of solidificationand solidification matrices. In particular, the present inventionrelates to salts of straight chain saturated mono-, di-, andtri-carboxylic acids as part of a solidification matrix.

The use of solidification technology and solid block detergents ininstitutional and industrial operations was pioneered in the SOLIDPOWER® brand technology claimed in Fernholz et al., U.S. Reissue Pat.Nos. 32,762 and 32,818. Additionally, sodium carbonate hydrate castsolid products using substantially hydrated sodium carbonate materialswas disclosed in Heile et al., U.S. Pat. Nos. 4,595,520 and 4,680,134.

In more recent years, attention has been directed to producing highlyeffective detergent materials from less caustic materials such as sodaash, also known as sodium carbonate. Early work in developing the sodiumcarbonate based detergents found that sodium carbonate hydrate-basedmaterials often swelled, (i.e., were dimensionally unstable) aftersolidification. Such swelling can interfere with packaging, dispensing,and use. The dimensional instability of the solid materials relates tothe unstable nature of various hydrate forms prepared in manufacturingthe sodium carbonate solid materials. Early products made with hydratedsodium carbonate typically comprised of anhydrous, a one mole hydrate, aseven mole hydrate, a ten mole hydrate or more mixtures thereof.However, after the product had been manufactured and stored at ambienttemperatures, the hydration state of the initial product was found toshift between hydrate forms, e.g., one, seven, and ten mole hydrates,resulting in dimensional instability of the block chemicals. In theseconventional solid form compositions, changes in water content andtemperature lead to structural and dimensional change, which may lead toa failure of the solid form, resulting in problems such as the inabilityof the solid form to fit into dispensers for use.

Additionally, conventional solid alkaline detergents, particularly thoseintended for institutional and commercial use, generally requirephosphates in their compositions. The phosphates typically servemultiple purposes in the compositions, for example, to control the rateof solidification, to remove and suspend soils, and as an effectivehardness sequestrant. It was found, disclosed, and claimed in U.S. Pat.Nos. 6,258,765, 6,156,715, 6,150,324, and 6,177,392, that a solid blockfunctional material could be made using a binding agent that includes acarbonate salt, an organic acetate, such as an aminocarboxylate, orphosphonate component and water. Due to ecological concerns, furtherwork has recently been directed to replacing phosphorous-containingcompounds in detergents. In addition, nitrilotriacetic acid(NTA)-containing aminocarboxylate components used in place ofphosphorous-containing compounds in some instances as a binding agentsand hardness sequestrants, are believed to be carcinogenic. As such,their use has also been curtailed.

There is an ongoing need to provide alternative solidificationtechnologies which are phosphorous-free and/or NTA-free. However, thelack of predictability in the solidification process and the lack ofpredictability of dimensional stability in solid form compositions havehampered efforts to successfully replace phosphorous and/orNTA-containing components with environmentally-friendly substitutes.

SUMMARY

A solidification matrix includes a straight chain saturated carboxylicacid salt, sodium carbonate, and water. The straight chain saturatedcarboxylic acid salt is selected from a salt of a mono-, di-, ortri-carboxylic acid. The solidification matrix may be used, for example,in a solid detergent composition.

DETAILED DESCRIPTION

The solidification matrix of the present invention may be employed inany of a wide variety of situations in which a dimensionally stablesolid product is desired. The solidification matrix is dimensionallystable and has an appropriate rate of solidification. In addition, thesolidification matrix may be substantially free of phosphorous and NTA,making the solidification matrix particularly useful in cleaningapplications where it is desired to use an environmentally friendlydetergent. Such applications include, but are not limited to: machineand manual warewashing, presoaks, laundry and textile cleaning anddestaining, carpet cleaning and destaining, vehicle cleaning and careapplications, surface cleaning and destaining, kitchen and bath cleaningand destaining, floor cleaning and destaining, cleaning in placeoperations, general purpose cleaning and destaining, industrial orhousehold cleaners, and pest control agents. Methods suitable forpreparing a solid detergent composition using the solidification matrixare also provided.

The solidification matrix generally includes a straight chain saturatedmono-, di-, or tri-carboxylic acid salt, sodium carbonate (soda ash),and water for forming solid compositions. Suitable componentconcentrations for the solidification matrix range from betweenapproximately 1% and approximately 15% by weight of a saturated straightchain saturated mono-, di-, or tri-carboxylic acid salt, betweenapproximately 2% and approximately 50% by weight water, and betweenapproximately 20% and approximately 70% by weight sodium carbonate.Particularly suitable component concentrations for the solidificationmatrix range from between approximately 1% and approximately 12% of asalt of a saturated straight chain saturated mono-, di-, ortri-carboxylic acid, between approximately 5% and approximately 40% byweight water, and between approximately 45% and approximately 65% byweight sodium carbonate. More particularly suitable componentconcentrations for the solidification matrix range from betweenapproximately 1% and approximately 10% of a salt of a saturated straightchain saturated mono-, di-, or tri-carboxylic acid, betweenapproximately 5% and approximately 35% by weight water, and betweenapproximately 50% and approximately 60% by weight sodium carbonate.Those skilled in the art will appreciate other suitable componentconcentration ranges for obtaining comparable properties of thesolidification matrix.

The actual solidification mechanism of the solidification matrix occursthrough ash hydration, or the interaction of the sodium carbonate withwater. It is believed that the straight chain saturated mono-, di-, ortri-carboxylic acid salt functions to control the kinetics andthermodynamics of the solidification process and provides asolidification matrix in which additional functional materials may bebound to form a functional solid composition. The straight chainsaturated mono-, di-, or tri-carboxylic acid salt may stabilize thecarbonate hydrates and the functional solid composition by acting as adonor and/or acceptor of free water. By controlling the rate of watermigration for hydration of the ash, the straight chain saturated mono-,di-, or tri-carboxylic acid salt may control the rate of solidificationto provide process and dimensional stability to the resulting product.The rate of solidification is significant because if the solidificationmatrix solidifies too quickly, the composition may solidify duringmixing and stop processing. If the solidification matrix solidifies tooslowly, valuable process time is lost. The straight chain saturatedmono-, di-, or tri-carboxylic acid salt also provides dimensionalstability to the end product by ensuring that the solid product does notswell. If the solid product swells after solidification, variousproblems may occur, including but not limited to: decreased density,integrity, and appearance; and inability to dispense or package thesolid product. Generally, a solid product is considered to havedimensional stability if the solid product has a growth exponent of lessthan about 3% and particularly less than about 2%.

The straight chain saturated mono-, di-, or tri-carboxylic acid salt iscombined with water prior to incorporation into the detergentcomposition and can be provided as a solid hydrate or as a solid saltthat is solvated in an aqueous solution, e.g., in a liquid premix.However, the straight chain saturated mono-, di-, or tri-carboxylic acidsalt should be in a water matrix when added to the detergent compositionfor the detergent composition to effectively solidify. In general, aneffective amount of straight chain saturated mono-, di-, ortri-carboxylic acid salt is considered an amount that effectivelycontrols the kinetics and thermodynamics of the solidification system bycontrolling the rate and movement of water. Examples of particularlysuitable salts of straight chain saturated monocarboxylic acids include,but are not limited to salts of acetic acid and salts of gluconic acid.Examples of particularly suitable salts of straight chain saturateddicarboxylic acids include, but are not limited to: salts of tartarticacid, salts of malic acid, salts of succinic acid, salts of glutaricacid, and salts of adipic acid. An example of a particularly suitablesalt of a straight chain saturated tricarboxylic acid includes, but isnot limited to, a salt of citric acid.

Water may be independently added to the solidification matrix or may beprovided in the solidification matrix as a result of its presence in anaqueous material that is added to the detergent composition. Forexample, materials added to the detergent composition may include wateror may be prepared in an aqueous premix available for reaction with thesolidification matrix component(s). Typically, water is introduced intothe solidification matrix to provide the solidification matrix with adesired viscosity for processing prior to solidification and to providea desired rate of solidification. The water may also be present as aprocessing aid and may be removed or become water of hydration. Thewater may thus be present in the form of aqueous solutions of thesolidification matrix, or aqueous solutions of any of the otheringredients, and/or added aqueous medium as an aid in processing. Inaddition, it is expected that the aqueous medium may help in thesolidification process when is desired to form the concentrate as asolid. The water may also be provided as deionized water or as softenedwater.

The amount of water in the resulting solid detergent composition willdepend on whether the solid detergent composition is processed throughforming techniques or casting (solidification occurring within acontainer) techniques. In general, when the components are processed byforming techniques, it is believed that the solid detergent compositioncan include a relatively smaller amount of water for solidificationcompared with the casting techniques. When preparing the solid detergentcomposition by forming techniques, water may be present in ranges ofbetween about 5% and about 25% by weight, particularly between about 7%and about 20% by weight, and more particularly between about 8% andabout 15% by weight. When preparing the solid detergent composition bycasting techniques, water may be present in the ranges of between about15% and about 50% by weight, particularly between about 20% and about45% by weight, and more particularly between about 22% and about 40% byweight.

The solidification matrix and resulting solid detergent composition mayalso exclude phosphorus or nitrilotriacetic acid (NTA) containingcompounds, to make the solid detergent composition more environmentallyacceptable. Phosphorus-free refers to a composition, mixture, oringredients to which phosphorus-containing compounds are not added.Should phosphorus-containing compounds be present through contaminationof a phosphorus-free composition, mixture, or ingredient, the level ofphosphorus-containing compounds in the resulting composition is lessthan approximately 0.5 wt %, less than approximately 0.1 wt %, and oftenless than approximately 0.01 wt %. NTA-free refers to a composition,mixture, or ingredients to which NTA-containing compounds are not added.Should NTA-containing compounds be present through contamination of anNTA-free composition, mixture, or ingredient, the level of NTA in theresulting composition shall be less than approximately 0.5 wt %, lessthan approximately 0.1 wt %, and often less than approximately 0.01 wt%. When the solidification matrix is NTA-free, the solidification matrixand resulting solid detergent composition is also compatible withchlorine, which functions as an anti-redeposition and stain-removalagent.

Additional Functional Materials

The hydrated solidification matrix, or binding agent, can be used toform a solid detergent composition including additional components oragents, such as additional functional materials. As such, in someembodiments, the solidification matrix including the straight chainsaturated mono-, di-, or tri-carboxylic acid salt, water, and sodiumcarbonate may provide a large amount, or even all of the total weight ofthe detergent composition, for example, in embodiments having few or noadditional functional materials disposed therein. The functionalmaterials provide desired properties and functionalities to the soliddetergent composition. For the purpose of this application, the term“functional materials” includes a material that when dispersed ordissolved in a use and/or concentrate solution, such as an aqueoussolution, provides a beneficial property in a particular use. Someparticular examples of functional materials are discussed in more detailbelow, although the particular materials discussed are given by way ofexample only, and that a broad variety of other functional materials maybe used. For example, many of the functional materials discussed belowrelate to materials used in cleaning and/or destaining applications.However, other embodiments may include functional materials for use inother applications.

Alkaline Source

The solid detergent composition can include an effective amount of oneor more alkaline sources to enhance cleaning of a substrate and improvesoil removal performance of the solid detergent composition. In general,it is expected that the composition will include the alkaline source inan amount of at least about 5% by weight, at least about 10% by weight,or at least about 15% by weight. In order to provide sufficient room forother components in the concentrate, the alkaline source can be providedin the concentrate in an amount of less than about 75% by weight, lessthan about 60% by weight, less than about 40% by weight, less than about30% by weight, or less than about 20% by weight. The alkalinity sourcemay constitute between about 0.1% and about 90% by weight, between about0.5% and about 80% by weight, and between about 1% and about 60% byweight of the total weight of the solid detergent composition.

An effective amount of one or more alkaline sources should be consideredas an amount that provides a use composition having a pH of at leastabout 8. When the use composition has a pH of between about 8 and about10, it can be considered mildly alkaline, and when the pH is greaterthan about 12, the use composition can be considered caustic. Ingeneral, it is desirable to provide the use composition as a mildlyalkaline cleaning composition because it is considered to be safer thanthe caustic based use compositions. In some circumstances, the soliddetergent composition may provide a use composition that is useful at pHlevels below about 8. In such compositions, the alkaline source may beomitted, and additional pH adjusting agents may be used to provide theuse composition with the desired pH.

Examples of suitable alkaline sources of the solid detergent compositioninclude, but are not limited to an alkali metal carbonate and an alkalimetal hydroxide. Exemplary alkali metal carbonates that can be usedinclude, but are not limited to: sodium or potassium carbonate,bicarbonate, sesquicarbonate, and mixtures thereof. Exemplary alkalimetal hydroxides that can be used include, but are not limited tosodium, lithium, or potassium hydroxide. The alkali metal hydroxide maybe added to the composition in any form known in the art, including assolid beads, dissolved in an aqueous solution, or a combination thereof.Alkali metal hydroxides are commercially available as a solid in theform of prilled solids or beads having a mix of particle sizes rangingfrom about 12-100 U.S. mesh, or as an aqueous solution, as for example,as a 50% and a 73% by weight solution. It is preferred that the alkalimetal hydroxide is added in the form of an aqueous solution,particularly a 50% by weight hydroxide solution, to reduce the amount ofheat generated in the composition due to hydration of the solid alkalimaterial.

In addition to the first alkalinity source, the solid detergentcomposition may comprise a secondary alkalinity source. Examples ofuseful secondary alkaline sources include, but are not limited to: metalsilicates such as sodium or potassium silicate or metasilicate; metalcarbonates such as sodium or potassium carbonate, bicarbonate,sesquicarbonate; metal borates such as sodium or potassium borate; andethanolamines and amines. Such alkalinity agents are commonly availablein either aqueous or powdered form, either of which is useful informulating the present solid detergent compositions.

Surfactants

The solid detergent composition can include at least one cleaning agentcomprising a surfactant or surfactant system. A variety of surfactantscan be used in a solid detergent composition, including, but not limitedto: anionic, nonionic, cationic, and zwitterionic surfactants.Surfactants are an optional component of the solid detergent compositionand can be excluded from the concentrate. Exemplary surfactants that canbe used are commercially available from a number of sources. For adiscussion of surfactants, see Kirk-Othmer, Encyclopedia of ChemicalTechnology, Third Edition, volume 8, pages 900-912. When the soliddetergent composition includes a cleaning agent, the cleaning agent isprovided in an amount effective to provide a desired level of cleaning.The solid detergent composition, when provided as a concentrate, caninclude the cleaning agent in a range of about 0.05% to about 20% byweight, about 0.5% to about 15% by weight, about 1% to about 15% byweight, about 1.5% to about 10% by weight, and about 2% to about 5% byweight. Additional exemplary ranges of surfactant in a concentrateinclude about 0.5% to about 5% by weight, and about 1% to about 3% byweight.

Examples of anionic surfactants useful in the solid detergentcomposition include, but are not limited to: carboxylates such asalkylcarboxylates and polyalkoxycarboxylates, alcohol ethoxylatecarboxylates, nonylphenol ethoxylate carboxylates; sulfonates such asalkylsulfonates, alkylbenzenesulfonates, alkylarylsulfonates, sulfonatedfatty acid esters; sulfates such as sulfated alcohols, sulfated alcoholethoxylates, sulfated alkylphenols, alkylsulfates, sulfosuccinates, andalkylether sulfates. Exemplary anionic surfactants include, but are notlimited to: sodium alkylarylsulfonate, alpha-olefinsulfonate, and fattyalcohol sulfates.

Examples of nonionic surfactants useful in the solid detergentcomposition include, but are not limited to, those having a polyalkyleneoxide polymer as a portion of the surfactant molecule. Such nonionicsurfactants include, but are not limited to: chlorine-, benzyl-,methyl-, ethyl-, propyl-, butyl- and other like alkyl-cappedpolyethylene glycol ethers of fatty alcohols; polyalkylene oxide freenonionics such as alkyl polyglycosides; sorbitan and sucrose esters andtheir ethoxylates; alkoxylated amines such as alkoxylated ethylenediamine; alcohol alkoxylates such as alcohol ethoxylate propoxylates,alcohol propoxylates, alcohol propoxylate ethoxylate propoxylates,alcohol ethoxylate butoxylates; nonylphenol ethoxylate, polyoxyethyleneglycol ether; carboxylic acid esters such as glycerol esters,polyoxyethylene esters, ethoxylated and glycol esters of fatty acids;carboxylic amides such as diethanolamine condensates, monoalkanolaminecondensates, polyoxyethylene fatty acid amides; and polyalkylene oxideblock copolymers. An example of a commercially available ethyleneoxide/propylene oxide block copolymer includes, but is not limited to,PLURONIC®, available from BASF Corporation, Florham Park, N.J. Anexample of a commercially available silicone surfactant includes, but isnot limited to, ABIL® B8852, available from Goldschmidt ChemicalCorporation, Hopewell, Va.

Examples of cationic surfactants that can be used in the solid detergentcomposition include, but are not limited to: amines such as primary,secondary and tertiary monoamines with C₁₈ alkyl or alkenyl chains,ethoxylated alkylamines, alkoxylates of ethylenediamine, imidazoles suchas a 1-(2-hydroxyethyl)-2-imidazoline, a2-alkyl-1-(2-hydroxyethyl)-2-imidazoline, and the like; and quaternaryammonium salts, as for example, alkylquaternary ammonium chloridesurfactants such as n-alkyl(C₁₂-C₁₈)dimethylbenzyl ammonium chloride,n-tetradecyldimethylbenzylammonium chloride monohydrate, and anaphthylene-substituted quaternary ammonium chloride such asdimethyl-1-naphthylmethylammonium chloride. The cationic surfactant canbe used to provide sanitizing properties.

Examples of zwitterionic surfactants that can be used in the soliddetergent composition include, but are not limited to: betaines,imidazolines, and propionates.

Because the solid detergent composition is intended to be used in anautomatic dishwashing or warewashing machine, the surfactants selected,if any surfactant is used, can be those that provide an acceptable levelof foaming when used inside a dishwashing or warewashing machine. Soliddetergent compositions for use in automatic dishwashing or warewashingmachines are generally considered to be low-foaming compositions. Lowfoaming surfactants that provide the desired level of detersive activityare advantageous in an environment such as a dishwashing machine wherethe presence of large amounts of foaming can be problematic. In additionto selecting low foaming surfactants, defoaming agents can also beutilized to reduce the generation of foam. Accordingly, surfactants thatare considered low foaming surfactants can be used. In addition, othersurfactants can be used in conjunction with a defoaming agent to controlthe level of foaming.

Some surfactants can also function as secondary solidifying agents. Forexample, anionic surfactants which have high melting points provide asolid at the temperature of application. Anionic surfactants which havebeen found most useful include, but are not limited to: linear alkylbenzene sulfonate surfactants, alcohol sulfates, alcohol ether sulfates,and alpha olefin sulfonates. Generally, linear alkyl benzene sulfonatesare preferred for reasons of cost and efficiency. Amphoteric orzwitterionic surfactants are also useful in providing detergency,emulsification, wetting and conditioning properties. Representativeamphoteric surfactants include, but are not limited to:N-coco-3-aminopropionic acid and acid salts,N-tallow-3-iminodiproprionate salts, N-lauryl-3-iminodiproprionatedisodium salt, N-carboxymethyl-N-cocoalkyl-N-dimethylammonium hydroxide,N-carboxymethyl-N-dimethyl-N-(9-octadecenyl)ammonium hydroxide,(1-carboxyheptadecyl) trimethylammonium hydroxide,(1-carboxyundecyl)trimethylammonium hydroxide,N-cocoamidoethyl-N-hydroxyethylglycine sodium salt,N-hydroxyethyl-N-stearamidoglycine sodium salt,N-hydroxyethyl-N-lauramido-.beta.-alanine sodium salt,N-cocoamido-N-hydroxyethyl-.beta.-alanine sodium salt, mixed alcyclicamines and their ethoxylated and sulfated sodium salts,2-alkyl-1-carboxymethyl-1-hydroxyethyl-2-imidazolinium hydroxide sodiumsalt or free acid wherein the alkyl group may be nonyl, undecyl, andheptadecyl. Other useful amphoteric surfactants include, but are notlimited to: 1,1-bis(carboxymethyl)-2-undecyl-2-imidazolinium hydroxidedisodium salt and oleic acid-ethylenediamine condensate, propoxylatedand sulfated sodium salt, and amine oxide amphoteric surfactants.

Builders or Water Conditioners

The solid detergent composition can include one or more building agents,also called chelating or sequestering agents (e.g., builders),including, but not limited to: a condensed phosphate, a phosphonate, anaminocarboxylic acid, or a polyacrylate. In addition, when sodiumcitrate is included in the solid detergent composition, the sodiumcitrate may also function as a builder. In general, a chelating agent isa molecule capable of coordinating (i.e., binding) the metal ionscommonly found in natural water to prevent the metal ions frominterfering with the action of the other detersive ingredients of acleaning composition. Preferable levels of addition for builders thatcan also be chelating or sequestering agents are between about 0.1% toabout 70% by weight, about 1% to about 60% by weight, or about 1.5% toabout 50% by weight. If the solid detergent is provided as aconcentrate, the concentrate can include between approximately 1% toapproximately 60% by weight, between approximately 3% to approximately50% by weight, and between approximately 6% to approximately 45% byweight of the builders. Additional ranges of the builders includebetween approximately 3% to approximately 20% by weight, betweenapproximately 6% to approximately 15% by weight, between approximately25% to approximately 50% by weight, and between approximately 35% toapproximately 45% by weight.

Examples of condensed phosphates include, but are not limited to: sodiumand potassium orthophosphate, sodium and potassium pyrophosphate, sodiumtripolyphosphate, and sodium hexametaphosphate. A condensed phosphatemay also assist, to a limited extent, in solidification of the soliddetergent composition by fixing the free water present in thecomposition as water of hydration.

Examples of phosphonates included, but are not limited to:1-hydroxyethane-1,1-diphosphonic acid, CH₂C(OH)[PO(OH)₂]₂;aminotri(methylenephosphonic acid), N[CH₂ PO(OH)₂]₃;aminotri(methylenephosphonate), sodium salt (ATMP), N[CH₂PO(ONa)₂]₃;2-hydroxyethyliminobis(methylenephosphonic acid),HOCH₂CH₂N[CH₂PO(OH)₂]₂; diethylenetriaminepenta(methylenephosphonicacid), (HO)₂POCH₂N[CH₂CH₂N[CH₂ PO(OH)₂]₂]₂;diethylenetriaminepenta(methylenephosphonate), sodium salt (DTPMP),C₉H_((28-x))N₃Na_(x)O₁₅P₅ (x=7);hexamethylenediamine(tetramethylenephosphonate), potassium salt,C₁₀H_((28-x))N₂K_(x)O₁₂P₄ (x=6);bis(hexamethylene)triamine(pentamethylenephosphonic acid),(HO₂)POCH₂N[(CH₂)₂N[CH₂PO(OH)₂]₂]₂; and phosphorus acid, H₃PO₃. Apreferred phosphonate combination is ATMP and DTPMP. A neutralized oralkaline phosphonate, or a combination of the phosphonate with an alkalisource prior to being added into the mixture such that there is littleor no heat or gas generated by a neutralization reaction when thephosphonate is added is preferred.

The solid detergent compositions can contain a non-phosphorus basedbuilder. Although various components may include trace amounts ofphosphorous, a composition that is considered free of phosphorousgenerally does not include phosphate or phosphonate builder or chelatingcomponents as an intentionally added component. Carboxylates such ascitrate or gluconate are suitable. Useful aminocarboxylic acid materialscontaining little or no NTA include, but are not limited to:N-hydroxyethylaminodiacetic acid, ethylenediaminetetraacetic acid(EDTA), hydroxyethylenediaminetetraacetic acid,diethylenetriaminepentaacetic acid,N-hydroxyethyl-ethylenediaminetriacetic acid (HEDTA),diethylenetriaminepentaacetic acid (DTPA), and other similar acidshaving an amino group with a carboxylic acid substituent.

Water conditioning polymers can be used as non-phosphorus containingbuilders. Exemplary water conditioning polymers include, but are notlimited to: polycarboxylates. Exemplary polycarboxylates that can beused as builders and/or water conditioning polymers include, but are notlimited to: those having pendant carboxylate (—CO₂ ⁻) groups such aspolyacrylic acid, maleic acid, maleic/olefin copolymer, sulfonatedcopolymer or terpolymer, acrylic/maleic copolymer, polymethacrylic acid,acrylic acid-methacrylic acid copolymers, hydrolyzed polyacrylamide,hydrolyzed polymethacrylamide, hydrolyzed polyamide-methacrylamidecopolymers, hydrolyzed polyacrylonitrile, hydrolyzedpolymethacrylonitrile, and hydrolyzed acrylonitrile-methacrylonitrilecopolymers. For a further discussion of chelating agents/sequestrants,see Kirk-Othmer, Encyclopedia of Chemical Technology, Third Edition,volume 5, pages 339-366 and volume 23, pages 319-320, the disclosure ofwhich is incorporated by reference herein. These materials may also beused at substoichiometric levels to function as crystal modifiers

Hardening Agents

The solid detergent compositions can also include a hardening agent inaddition to, or in the form of, the builder. A hardening agent is acompound or system of compounds, organic or inorganic, whichsignificantly contributes to the uniform solidification of thecomposition. Preferably, the hardening agents are compatible with thecleaning agent and other active ingredients of the composition and arecapable of providing an effective amount of hardness and/or aqueoussolubility to the processed composition. The hardening agents shouldalso be capable of forming a homogeneous matrix with the cleaning agentand other ingredients when mixed and solidified to provide a uniformdissolution of the cleaning agent from the solid detergent compositionduring use.

The amount of hardening agent included in the solid detergentcomposition will vary according to factors including, but not limitedto: the type of solid detergent composition being prepared, theingredients of the solid detergent composition, the intended use of thecomposition, the quantity of dispensing solution applied to the solidcomposition over time during use, the temperature of the dispensingsolution, the hardness of the dispensing solution, the physical size ofthe solid detergent composition, the concentration of the otheringredients, and the concentration of the cleaning agent in thecomposition. It is preferred that the amount of the hardening agentincluded in the solid detergent composition is effective to combine withthe cleaning agent and other ingredients of the composition to form ahomogeneous mixture under continuous mixing conditions and a temperatureat or below the melting temperature of the hardening agent.

It is also preferred that the hardening agent form a matrix with thecleaning agent and other ingredients which will harden to a solid formunder ambient temperatures of approximately 30° C. to approximately 50°C., particularly approximately 35° C. to approximately 45° C., aftermixing ceases and the mixture is dispensed from the mixing system,within approximately 1 minute to approximately 3 hours, particularlyapproximately 2 minutes to approximately 2 hours, and particularlyapproximately 5 minutes to approximately 1 hour. A minimal amount ofheat from an external source may be applied to the mixture to facilitateprocessing of the mixture. It is preferred that the amount of thehardening agent included in the solid detergent composition is effectiveto provide a desired hardness and desired rate of controlled solubilityof the processed composition when placed in an aqueous medium to achievea desired rate of dispensing the cleaning agent from the solidifiedcomposition during use.

The hardening agent may be an organic or an inorganic hardening agent. Apreferred organic hardening agent is a polyethylene glycol (PEG)compound. The solidification rate of solid detergent compositionscomprising a polyethylene glycol hardening agent will vary, at least inpart, according to the amount and the molecular weight of thepolyethylene glycol added to the composition. Examples of suitablepolyethylene glycols include, but are not limited to: solid polyethyleneglycols of the general formula H(OCH₂CH₂)_(n)OH, where n is greater than15, particularly approximately 30 to approximately 1700. Typically, thepolyethylene glycol is a solid in the form of a free-flowing powder orflakes, having a molecular weight of approximately 1,000 toapproximately 100,000, particularly having a molecular weight of atleast approximately 1,450 to approximately 20,000, more particularlybetween approximately 1,450 to approximately 8,000. The polyethyleneglycol is present at a concentration of from approximately 1% to 75% byweight and particularly approximately 3% to approximately 15% by weight.Suitable polyethylene glycol compounds include, but are not limited to:PEG 4000, PEG 1450, and PEG 8000 among others, with PEG 4000 and PEG8000 being most preferred. An example of a commercially available solidpolyethylene glycol includes, but is not limited to: CARBOWAX, availablefrom Union Carbide Corporation, Houston, Tex.

Preferred inorganic hardening agents are hydratable inorganic salts,including, but not limited to: sulfates and bicarbonates. The inorganichardening agents are present at concentrations of up to approximately50% by weight, particularly approximately 5% to approximately 25% byweight, and more particularly approximately 5% to approximately 15% byweight.

Urea particles can also be employed as hardeners in the solid detergentcompositions. The solidification rate of the compositions will vary, atleast in part, to factors including, but not limited to: the amount, theparticle size, and the shape of the urea added to the composition. Forexample, a particulate form of urea can be combined with a cleaningagent and other ingredients, and preferably a minor but effective amountof water. The amount and particle size of the urea is effective tocombine with the cleaning agent and other ingredients to form ahomogeneous mixture without the application of heat from an externalsource to melt the urea and other ingredients to a molten stage. It ispreferred that the amount of urea included in the solid detergentcomposition is effective to provide a desired hardness and desired rateof solubility of the composition when placed in an aqueous medium toachieve a desired rate of dispensing the cleaning agent from thesolidified composition during use. In some embodiments, the compositionincludes between approximately 5% to approximately 90% by weight urea,particularly between approximately 8% and approximately 40% by weighturea, and more particularly between approximately 10% and approximately30% by weight urea.

The urea may be in the form of prilled beads or powder. Prilled urea isgenerally available from commercial sources as a mixture of particlesizes ranging from about 8-15 U.S. mesh, as for example, from ArcadianSohio Company, Nitrogen Chemicals Division. A prilled form of urea ispreferably milled to reduce the particle size to about 50 U.S. mesh toabout 125 U.S. mesh, particularly about 75-100 U.S. mesh, preferablyusing a wet mill such as a single or twin-screw extruder, a Teledynemixer, a Ross emulsifier, and the like.

Bleaching Agents

Bleaching agents suitable for use in the solid detergent composition forlightening or whitening a substrate include bleaching compounds capableof liberating an active halogen species, such as Cl₂, Br₂, —OCl⁻ and/or—OBr⁻, under conditions typically encountered during the cleansingprocess. Suitable bleaching agents for use in the solid detergentcompositions include, but are not limited to: chlorine-containingcompounds such as chlorines, hypochlorites, or chloramines. Exemplaryhalogen-releasing compounds include, but are not limited to: the alkalimetal dichloroisocyanurates, chlorinated trisodium phosphate, the alkalimetal hypochlorites, monochloramine, and dichloramine. Encapsulatedchlorine sources may also be used to enhance the stability of thechlorine source in the composition (see, for example, U.S. Pat. Nos.4,618,914 and 4,830,773, the disclosure of which is incorporated byreference herein). A bleaching agent may also be a peroxygen or activeoxygen source such as hydrogen peroxide, perborates, sodium carbonateperoxyhydrate, potassium permonosulfate, and sodium perborate mono andtetrahydrate, with and without activators such as tetraacetylethylenediamine. When the concentrate includes a bleaching agent, it can beincluded in an amount of between approximately 0.1% and approximately60% by weight, between approximately 1% and approximately 20% by weight,between approximately 3% and approximately 8% by weight, and betweenapproximately 3% and approximately 6% by weight.

Fillers

The solid detergent composition can include an effective amount ofdetergent fillers which do not perform as a cleaning agent per se, butcooperates with the cleaning agent to enhance the overall cleaningcapacity of the composition. Examples of detergent fillers suitable foruse in the present cleaning compositions include, but are not limitedto: sodium sulfate, sodium chloride, starch, and sugars. When theconcentrate includes a detergent filler, it can be included in an amountup to approximately 50% by weight, between approximately 1% andapproximately 30% by weight, or between approximately 1.5% andapproximately 25% by weight.

Defoaming Agents

A defoaming agent for reducing the stability of foam may also beincluded in the warewashing composition. Examples of defoaming agentsinclude, but are not limited to: ethylene oxide/propylene blockcopolymers such as those available under the name Pluronic N-3; siliconecompounds such as silica dispersed in polydimethylsiloxane,polydimethylsiloxane, and functionalized polydimethylsiloxane such asthose available under the name Abil B9952; fatty amides, hydrocarbonwaxes, fatty acids, fatty esters, fatty alcohols, fatty acid soaps,ethoxylates, mineral oils, polyethylene glycol esters, and alkylphosphate esters such as monostearyl phosphate. A discussion ofdefoaming agents may be found, for example, in U.S. Pat. No. 3,048,548to Martin et al., U.S. Pat. No. 3,334,147 to Brunelle et al., and U.S.Pat. No. 3,442,242 to Rue et al., the disclosures of which areincorporated herein by reference. When the concentrate includes adefoaming agent, the defoaming agent can be provided in an amount ofbetween approximately 0.0001% and approximately 10% by weight, betweenapproximately 0.001% and approximately 5% by weight, or betweenapproximately 0.01% and approximately 1.0% by weight.

Anti-Redeposition Agents

The solid detergent composition can include an anti-redeposition agentfor facilitating sustained suspension of soils in a cleaning solutionand preventing the removed soils from being redeposited onto thesubstrate being cleaned. Examples of suitable anti-redeposition agentsinclude, but are not limited to: polyacrylates, styrene maleic anhydridecopolymers, cellulosic derivatives such as hydroxyethyl cellulose, andhydroxypropyl cellulose. When the concentrate includes ananti-redeposition agent, the anti-redeposition agent can be included inan amount of between approximately 0.5% and approximately 10% by weight,and between approximately 1% and approximately 5% by weight.

Stabilizing Agents

The solid detergent composition may also include stabilizing agents.Examples of suitable stabilizing agents include, but are not limited to:borate, calcium/magnesium ions, propylene glycol, and mixtures thereof.The concentrate need not include a stabilizing agent, but when theconcentrate includes a stabilizing agent, it can be included in anamount that provides the desired level of stability of the concentrate.Exemplary ranges of the stabilizing agent include up to approximately20% by weight, between approximately 0.5% and approximately 15% byweight, and between approximately 2% and approximately 10% by weight.

Dispersants

The solid detergent composition may also include dispersants. Examplesof suitable dispersants that can be used in the solid detergentcomposition include, but are not limited to: maleic acid/olefincopolymers, polyacrylic acid, and mixtures thereof. The concentrate neednot include a dispersant, but when a dispersant is included it can beincluded in an amount that provides the desired dispersant properties.Exemplary ranges of the dispersant in the concentrate can be up toapproximately 20% by weight, between approximately 0.5% andapproximately 15% by weight, and between approximately 2% andapproximately 9% by weight.

Enzymes

Enzymes that can be included in the solid detergent composition includethose enzymes that aid in the removal of starch and/or protein stains.Exemplary types of enzymes include, but are not limited to: proteases,alpha-amylases, and mixtures thereof. Exemplary proteases that can beused include, but are not limited to: those derived from Bacilluslicheniformix, Bacillus lenus, Bacillus alcalophilus, and Bacillusamyloliquefacins. Exemplary alpha-amylases include Bacillus subtilis,Bacillus amyloliquefaceins and Bacillus licheniformis. The concentrateneed not include an enzyme, but when the concentrate includes an enzyme,it can be included in an amount that provides the desired enzymaticactivity when the solid detergent composition is provided as a usecomposition. Exemplary ranges of the enzyme in the concentrate includeup to approximately 15% by weight, between approximately 0.5% toapproximately 10% by weight, and between approximately 1% toapproximately 5% by weight.

Glass and Metal Corrosion Inhibitors

The solid detergent composition can include a metal corrosion inhibitorin an amount up to approximately 50% by weight, between approximately 1%and approximately 40% by weight, or between approximately 3% andapproximately 30% by weight. The corrosion inhibitor is included in thesolid detergent composition in an amount sufficient to provide a usesolution that exhibits a rate of corrosion and/or etching of glass thatis less than the rate of corrosion and/or etching of glass for anotherwise identical use solution except for the absence of the corrosioninhibitor. It is expected that the use solution will include at leastapproximately 6 parts per million (ppm) of the corrosion inhibitor toprovide desired corrosion inhibition properties. It is expected thatlarger amounts of corrosion inhibitor can be used in the use solutionwithout deleterious effects. It is expected that at a certain point, theadditive effect of increased corrosion and/or etching resistance withincreasing corrosion inhibitor concentration will be lost, andadditional corrosion inhibitor will simply increase the cost of usingthe solid detergent composition. The use solution can include betweenapproximately 6 ppm and approximately 300 ppm of the corrosioninhibitor, and between approximately 20 ppm and approximately 200 ppm ofthe corrosion inhibitor. Examples of suitable corrosion inhibitorsinclude, but are not limited to: a combination of a source of aluminumion and a source of zinc ion, as well as an alkaline metal silicate orhydrate thereof.

The corrosion inhibitor can refer to the combination of a source ofaluminum ion and a source of zinc ion. The source of aluminum ion andthe source of zinc ion provide aluminum ion and zinc ion, respectively,when the solid detergent composition is provided in the form of a usesolution. The amount of the corrosion inhibitor is calculated based uponthe combined amount of the source of aluminum ion and the source of zincion. Anything that provides an aluminum ion in a use solution can bereferred to as a source of aluminum ion, and anything that provides azinc ion when provided in a use solution can be referred to as a sourceof zinc ion. It is not necessary for the source of aluminum ion and/orthe source of zinc ion to react to form the aluminum ion and/or the zincion. Aluminum ions can be considered a source of aluminum ion, and zincions can be considered a source of zinc ion. The source of aluminum ionand the source of zinc ion can be provided as organic salts, inorganicsalts, and mixtures thereof. Exemplary sources of aluminum ion include,but are not limited to: aluminum salts such as sodium aluminate,aluminum bromide, aluminum chlorate, aluminum chloride, aluminum iodide,aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum formate,aluminum tartrate, aluminum lactate, aluminum oleate, aluminum bromate,aluminum borate, aluminum potassium sulfate, aluminum zinc sulfate, andaluminum phosphate. Exemplary sources of zinc ion include, but are notlimited to: zinc salts such as zinc chloride, zinc sulfate, zincnitrate, zinc iodide, zinc thiocyanate, zinc fluorosilicate, zincdichromate, zinc chlorate, sodium zincate, zinc gluconate, zinc acetate,zinc benzoate, zinc citrate, zinc lactate, zinc formate, zinc bromate,zinc bromide, zinc fluoride, zinc fluorosilicate, and zinc salicylate.

The applicants discovered that by controlling the ratio of the aluminumion to the zinc ion in the use solution, it is possible to providereduced corrosion and/or etching of glassware and ceramics compared withthe use of either component alone. That is, the combination of thealuminum ion and the zinc ion can provide a synergy in the reduction ofcorrosion and/or etching. The ratio of the source of aluminum ion to thesource of zinc ion can be controlled to provide a synergistic effect. Ingeneral, the weight ratio of aluminum ion to zinc ion in the usesolution can be between at least approximately 6:1, can be less thanapproximately 1:20, and can be between approximately 2:1 andapproximately 1:15.

An effective amount of an alkaline metal silicate or hydrate thereof canbe employed in the compositions and processes of the invention to form astable solid detergent composition having metal protecting capacity. Thesilicates employed in the compositions of the invention are those thathave conventionally been used in solid detergent formulations. Forexample, typical alkali metal silicates are those powdered, particulateor granular silicates which are either anhydrous or preferably whichcontain water of hydration (approximately 5% to approximately 25% byweight, particularly approximately 15% to approximately 20% by weightwater of hydration). These silicates are preferably sodium silicates andhave a Na₂O:SiO₂ ratio of approximately 1:1 to approximately 1:5,respectively, and typically contain available water in the amount offrom approximately 5% to approximately 25% by weight. In general, thesilicates have a Na₂O:SiO₂ ratio of approximately 1:1 to approximately1:3.75, particularly approximately 1:1.5 to approximately 1:3.75 andmost particularly approximately 1:1.5 to approximately 1:2.5. A silicatewith a Na₂O:SiO₂ ratio of approximately 1:2 and approximately 16% toapproximately 22% by weight water of hydration, is most preferred. Forexample, such silicates are available in powder form as GD Silicate andin granular form as Britesil H-20, available from PQ Corporation, ValleyForge, Pa. These ratios may be obtained with single silicatecompositions or combinations of silicates which upon combination resultin the preferred ratio. The hydrated silicates at preferred ratios, aNa₂O:SiO₂ ratio of approximately 1:1.5 to approximately 1:2.5, have beenfound to provide the optimum metal protection and rapidly form a soliddetergent. Hydrated silicates are preferred.

Silicates can be included in the solid detergent composition to providefor metal protection but are additionally known to provide alkalinityand additionally function as anti-redeposition agents. Exemplarysilicates include, but are not limited to: sodium silicate and potassiumsilicate. The solid detergent composition can be provided withoutsilicates, but when silicates are included, they can be included inamounts that provide for desired metal protection. The concentrate caninclude silicates in amounts of at least approximately 1% by weight, atleast approximately 5% by weight, at least approximately 10% by weight,and at least approximately 15% by weight. In addition, in order toprovide sufficient room for other components in the concentrate, thesilicate component can be provided at a level of less than approximately35% by weight, less than approximately 25% by weight, less thanapproximately 20% by weight, and less than approximately 15% by weight.

Fragrances and Dyes

Various dyes, odorants including perfumes, and other aesthetic enhancingagents can also be included in the composition. Suitable dyes that maybe included to alter the appearance of the composition, include, but arenot limited to: Direct Blue 86, available from Mac Dye-Chem Industries,Ahmedabad, India; Fastusol Blue, available from Mobay ChemicalCorporation, Pittsburgh, Pa.; Acid Orange 7, available from AmericanCyanamid Company, Wayne, N.J.; Basic Violet 10 and Sandolan Blue/AcidBlue 182, available from Sandoz, Princeton, N.J.; Acid Yellow 23,available from Chemos GmbH, Regenstauf, Germany; Acid Yellow 17,available from Sigma Chemical, St. Louis, Mo.; Sap Green and MetanilYellow, available from Keyston Analine and Chemical, Chicago, Ill.; AcidBlue 9, available from Emerald Hilton Davis, LLC, Cincinnati, Ohio;Hisol Fast Red and Fluorescein, available from Capitol Color andChemical Company, Newark, N.J.; and Acid Green 25, Ciba SpecialtyChemicals Corporation, Greenboro, N.C.

Fragrances or perfumes that may be included in the compositions include,but are not limited to: terpenoids such as citronellol, aldehydes suchas amyl cinnamaldehyde, a jasmine such as C1S-jasmine or jasmal, andvanillin.

Thickeners

The solid detergent compositions can include a rheology modifier or athickener. The rheology modifier may provide the following functions:increasing the viscosity of the compositions; increasing the particlesize of liquid use solutions when dispensed through a spray nozzle;providing the use solutions with vertical cling to surfaces; providingparticle suspension within the use solutions; or reducing theevaporation rate of the use solutions.

The rheology modifier may provide a use composition that is pseudoplastic, in other words the use composition or material when leftundisturbed (in a shear mode), retains a high viscosity. However, whensheared, the viscosity of the material is substantially but reversiblyreduced. After the shear action is removed, the viscosity returns. Theseproperties permit the application of the material through a spray head.When sprayed through a nozzle, the material undergoes shear as it isdrawn up a feed tube into a spray head under the influence of pressureand is sheared by the action of a pump in a pump action sprayer. Ineither case, the viscosity can drop to a point such that substantialquantities of the material can be applied using the spray devices usedto apply the material to a soiled surface. However, once the materialcomes to rest on a soiled surface, the materials can regain highviscosity to ensure that the material remains in place on the soil.Preferably, the material can be applied to a surface resulting in asubstantial coating of the material that provides the cleaningcomponents in sufficient concentration to result in lifting and removalof the hardened or baked-on soil. While in contact with the soil onvertical or inclined surfaces, the thickeners in conjunction with theother components of the cleaner minimize dripping, sagging, slumping orother movement of the material under the effects of gravity. Thematerial should be formulated such that the viscosity of the material isadequate to maintain contact between substantial quantities of the filmof the material with the soil for at least a minute, particularly fiveminutes or more.

Examples of suitable thickeners or rheology modifiers are polymericthickeners including, but not limited to: polymers or natural polymersor gums derived from plant or animal sources. Such materials may bepolysaccharides such as large polysaccharide molecules havingsubstantial thickening capacity. Thickeners or rheology modifiers alsoinclude clays.

A substantially soluble polymeric thickener can be used to provideincreased viscosity or increased conductivity to the use compositions.Examples of polymeric thickeners for the aqueous compositions of theinvention include, but are not limited to: carboxylated vinyl polymerssuch as polyacrylic acids and sodium salts thereof, ethoxylatedcellulose, polyacrylamide thickeners, cross-linked, xanthancompositions, sodium alginate and algin products, hydroxypropylcellulose, hydroxyethyl cellulose, and other similar aqueous thickenersthat have some substantial proportion of water solubility. Examples ofsuitable commercially available thickeners include, but are not limitedto: Acusol, available from Rohm & Haas Company, Philadelphia, Pa.; andCarbopol, available from B.F. Goodrich, Charlotte, N.C.

Examples of suitable polymeric thickeners include, but not limited to:polysaccharides. An example of a suitable commercially availablepolysaccharide includes, but is not limited to, Diutan, available fromKelco Division of Merck, San Diego, Calif. Thickeners for use in thesolid detergent compositions further include polyvinyl alcoholthickeners, such as, fully hydrolyzed (greater than 98.5 mol acetatereplaced with the —OH function).

An example of a particularly suitable polysaccharide includes, but isnot limited to, xanthans. Such xanthan polymers are preferred due totheir high water solubility, and great thickening power. Xanthan is anextracellular polysaccharide of xanthomonas campestras. Xanthan may bemade by fermentation based on corn sugar or other corn sweetenerby-products. Xanthan comprises a poly beta-(1-4)-D-Glucopyranosylbackbone chain, similar to that found in cellulose. Aqueous dispersionsof xanthan gum and its derivatives exhibit novel and remarkablerheological properties. Low concentrations of the gum have relativelyhigh viscosities which permit it to be used economically. Xanthan gumsolutions exhibit high pseudo plasticity, i.e. over a wide range ofconcentrations, rapid shear thinning occurs that is generally understoodto be instantaneously reversible. Non-sheared materials have viscositiesthat appear to be independent of the pH and independent of temperatureover wide ranges. Preferred xanthan materials include crosslinkedxanthan materials. Xanthan polymers can be crosslinked with a variety ofknown covalent reacting crosslinking agents reactive with the hydroxylfunctionality of large polysaccharide molecules and can also becrosslinked using divalent, trivalent or polyvalent metal ions. Suchcrosslinked xanthan gels are disclosed in U.S. Pat. No. 4,782,901, whichis herein incorporated by reference. Suitable crosslinking agents forxanthan materials include, but are not limited to: metal cations such asAl+3, Fe+3, Sb+3, Zr+4 and other transition metals. Examples of suitablecommercially available xanthans include, but are not limited to:KELTROL®, KELZAN® AR, KELZAN® D35, KELZAN® S, KELZAN® XZ, available fromKelco Division of Merck, San Diego, Calif. Known organic crosslinkingagents can also be used. A preferred crosslinked xanthan is KELZAN® AR,which provides a pseudo plastic use solution that can produce largeparticle size mist or aerosol when sprayed.

Methods of Use

In general, a solid detergent composition using the solidificationmatrix of the present invention can be created by combining a salt of astraight chain saturated mono-, di-, or tri-carboxylic acid, sodiumcarbonate, water, and any additional functional components and allowingthe components to interact and solidify. For example, in a firstembodiment, the solid detergent composition may include a salt of astraight chain saturated mono-, di-, or tri-carboxylic acid, water,builder, sodium carbonate, and surfactant. In an exemplary embodiment,the solid detergent composition includes between about 1% and about 15%straight chain saturated mono-, di-, or tri-carboxylic acid salt byweight and particularly between about 1% and about 10% straight chainsaturated mono-, di-, or tri-carboxylic acid salt by weight. In anotherexemplary embodiment, the solid detergent composition includes betweenabout 2% and about 50% water by weight and particularly between about 5%and about 40% water by weight. In another exemplary embodiment, thesolid detergent composition includes less than about 40% builder byweight and particularly less than about 30% builder by weight. Inanother exemplary embodiment, the solid detergent composition includesbetween about 20% and about 70% sodium carbonate by weight andparticularly between about 45% and about 65% sodium carbonate by weight.In another exemplary embodiment, the solid detergent compositionincludes between about 0.5% and about 10% surfactant by weight andparticularly between about 1% and about 5% surfactant by weight.

In some embodiments, the relative amounts of water and straight chainsaturated mono-, di-, or tri-carboxylic acid salt are controlled withina composition. The solidification matrix and additional functionalcomponents harden into solid form due to the chemical reaction of thesodium carbonate with the water. As the solidification matrixsolidifies, a binder composition can form to bind and solidify thecomponents. At least a portion of the ingredients associate to form thebinder while the balance of the ingredients forms the remainder of thesolid composition. The solidification process may last from a fewminutes to about six hours, depending on factors including, but notlimited to: the size of the formed or cast composition, the ingredientsof the composition, and the temperature of the composition.

Solid detergent compositions formed using the solidification matrix areproduced using a batch or continuous mixing system. In an exemplaryembodiment, a single- or twin-screw extruder is used to combine and mixone or more cleaning agents at high shear to form a homogeneous mixture.In some embodiments, the processing temperature is at or below themelting temperature of the components. The processed mixture may bedispensed from the mixer by forming, casting or other suitable means,whereupon the detergent composition hardens to a solid form. Thestructure of the matrix may be characterized according to its hardness,melting point, material distribution, crystal structure, and other likeproperties according to known methods in the art. Generally, a soliddetergent composition processed according to the method of the inventionis substantially homogeneous with regard to the distribution ofingredients throughout its mass and is dimensionally stable.

Specifically, in a forming process, the liquid and solid components areintroduced into the final mixing system and are continuously mixed untilthe components form a substantially homogeneous semi-solid mixture inwhich the components are distributed throughout its mass. In anexemplary embodiment, the components are mixed in the mixing system forat least approximately 5 seconds. The mixture is then discharged fromthe mixing system into, or through, a die or other shaping means. Theproduct is then packaged. In an exemplary embodiment, the formedcomposition begins to harden to a solid form in between approximately 1minute and approximately 3 hours. Particularly, the formed compositionbegins to harden to a solid form in between approximately 1 minute andapproximately 2 hours. More particularly, the formed composition beginsto harden to a solid form in between approximately 1 minute andapproximately 20 minutes.

Specifically, in a casting process, the liquid and solid components areintroduced into the final mixing system and are continuously mixed untilthe components form a substantially homogeneous liquid mixture in whichthe components are distributed throughout its mass. In an exemplaryembodiment, the components are mixed in the mixing system for at leastapproximately 60 seconds. Once the mixing is complete, the product istransferred to a packaging container where solidification takes place.In an exemplary embodiment, the cast composition begins to harden to asolid form in between approximately 1 minute and approximately 3 hours.Particularly, the cast composition begins to harden to a solid form inbetween approximately 1 minute and approximately 2 hours. Moreparticularly, the cast composition begins to harden to a solid form inbetween approximately 1 minute and approximately 20 minutes.

By the term “solid form”, it is meant that the hardened composition willnot flow and will substantially retain its shape under moderate stressor pressure or mere gravity. The degree of hardness of the solid castcomposition may range from that of a fused solid product which isrelatively dense and hard, for example, like concrete, to a consistencycharacterized as being a hardened paste. In addition, the term “solid”refers to the state of the detergent composition under the expectedconditions of storage and use of the solid detergent composition. Ingeneral, it is expected that the detergent composition will remain insolid form when exposed to temperatures of up to approximately 100° F.and particularly greater than approximately 120° F.

The resulting solid detergent composition may take forms including, butnot limited to: a cast solid product; an extruded, molded or formedsolid pellet, block, tablet, powder, granule, flake; or the formed solidcan thereafter be ground or formed into a powder, granule, or flake. Inan exemplary embodiment, extruded pellet materials formed by thesolidification matrix have a weight of between approximately 50 gramsand approximately 250 grams, extruded solids formed by thesolidification matrix have a weight of approximately 100 grams orgreater, and solid block detergents formed by the solidification matrixhave a mass of between approximately 1 and approximately 10 kilograms.The solid compositions provide for a stabilized source of functionalmaterials. In some embodiments, the solid composition may be dissolved,for example, in an aqueous or other medium, to create a concentratedand/or use solution. The solution may be directed to a storage reservoirfor later use and/or dilution, or may be applied directly to a point ofuse.

In certain embodiments, the solid detergent composition is provided inthe form of a unit dose. A unit dose refers to a solid detergentcomposition unit sized so that the entire unit is used during a singlewashing cycle. When the solid detergent composition is provided as aunit dose, it is typically provided as a cast solid, an extruded pellet,or a tablet having a size of between approximately 1 gram andapproximately 50 grams.

In other embodiments, the solid detergent composition is provided in theform of a multiple-use solid, such as a block or a plurality of pellets,and can be repeatedly used to generate aqueous detergent compositionsfor multiple washing cycles. In certain embodiments, the solid detergentcomposition is provided as a cast solid, an extruded block, or a tablethaving a mass of between approximately 5 grams and approximately 10kilograms. In certain embodiments, a multiple-use form of the soliddetergent composition has a mass between approximately 1 kilogram andapproximately 10 kilograms. In further embodiments, a multiple-use formof the solid detergent composition has a mass of between approximately 5kilograms and about approximately 8 kilograms. In other embodiments, amultiple-use form of the solid detergent composition has a mass ofbetween about approximately 5 grams and approximately 1 kilogram, orbetween approximately 5 grams and approximately 500 grams.

Although the detergent composition is discussed as being formed into asolid product, the detergent composition may also be provided in theform of a paste. When the concentrate is provided in the form of apaste, enough water is added to the detergent composition such thatcomplete solidification of the detergent composition is precluded. Inaddition, dispersants and other components may be incorporated into thedetergent composition in order to maintain a desired distribution ofcomponents.

EXAMPLES

The present invention is more particularly described in the followingexamples that are intended as illustrations only, since numerousmodifications and variations within the scope of the present inventionwill be apparent to those skilled in the art. Unless otherwise noted,all parts, percentages, and ratios reported in the following examplesare on a weight basis, and all reagents used in the examples wereobtained, or are available, from the chemical suppliers described below,or may be synthesized by conventional techniques.

The following test method was used to characterize the compositionsproduced in Examples 1, 2, and 3 and Comparative Example A:

Dimensional Stability Test for Formed Products

Approximately 50 grams batch of the product using a straight chainsaturated mono-, di-, or tri-carboxylic acid salt as part of thesolidification matrix was first pressed in a die at approximately 1000pounds per square inch (psi) for approximately 20 seconds to formtablets. The diameter and height of the tablets were measured andrecorded. The tablets were maintained at room temperature for one dayand then placed in an oven at a temperature of approximately 120° F.After the tablets were removed from the oven, the diameters and heightsof the tablets were measured and recorded. The tablets were consideredto exhibit dimensional stability if there was less than approximately 2%swelling, or growth.

Examples 1, 2 and 3 and Comparative Example A

Examples 1, 2, and 3 are compositions of the present invention using astraight chain saturated mono-, di-, or tri-carboxylic acid salt as partof a solidification matrix. In particular, the compositions of Examples1, 2, and 3 used sodium citrate dihydrate, sodium tartrate dihydrate,and sodium acetate, respectively, as part of the solidification matrix.In addition, the compositions of Examples 1-3 also included componentconcentrations (in weight percent) of sodium carbonate (soda ash ordense ash), sodium bicarbonate, anhydrous metasilicate, a builder, andsurfactants as provided in Table 1. The sodium carbonate, sodiumbicarbonate, anhydrous metasilicate, sodium citrate dihydrate,copolymer, and surfactants were premixed to form a powder premix and thestraight chain saturated mono-, di-, or tri-carboxylic acid salt andwater were premixed to form a liquid premix. The powder premix and theliquid premix were then mixed together to form the composition.Approximately 50 grams of the composition were pressed into a tablet atapproximately 1000 psi for approximately 20 seconds.

The composition of Comparative Example A was prepared as in Examples 1,2, and 3, except that the composition of Comparative Example A did notinclude a straight chain saturated mono-, di-, or tri-carboxylic acidsalt.

Table 1 provides the component concentrations for the compositions ofExample 1, Example 2, Example 3, and Comparative Example A.

TABLE 1 Exam- Exam- Exam- Comp. Component ple 1 ple 2 ple 3 Example ASodium carbonate, wt. % 54.6 54.55 51.55 57.21 Sodium bicarbonate, wt. %2.88 2.88 2.88 2.88 Anhydrous metasilicate, 3 3 3 3 wt. % Builder, wt. %20 20 20 20 Copolymer, wt. % 0.98 1.98 0.98 1.98 Nonionic surfactant,wt. % 3.53 3.53 3.53 3.53 Defoamer, wt. % 1.06 1.06 1.06 1.06 Sodiumcitrate dihydrate, 5.19 0.00 0.00 0.00 wt. % Sodium tartrate dihydrate,0.00 1.4 0.00 0.00 wt. % Sodium acetate, wt. % 0.00 0.00 9.39 0.00Water, wt. % 8.76 12.6 7.61 11.34

The compositions of Examples 1, 2, and 3 and Comparative Example A werethen subjected to the dimensional stability test for formed products, asdiscussed above, to observe the dimensional stability of thecompositions after heating. The results are tabulated below in Table 2.

TABLE 2 Initial Post-heating % Growth Example 1 Diameter, mm 15.17 45.330.3 Height, mm 19.15 19.17 0.1 Example 2 Diameter, mm 44.69 44.86 0.4Height, mm 21.03 21.07 0.1 Example 3 Diameter, mm 45.38 45.46 0.1Height, mm 20 20.08 0.4 Comparative Diameter, mm 44.77 46 2.7 Example AHeight, mm 19.38 20.96 8.2

As illustrated in Table 2, the formed products of the compositions ofExamples 1, 2, and 3 exhibited considerably less swelling than theformed product of the composition of Comparative Example A. Inparticular, the product of the composition of Example 1 had only a 0.3%growth in diameter and a 0.1% growth in height, the product of thecomposition of Example 2 only had a 0.4% growth in diameter and a 0.1%growth in height, and the product of the composition of Example 3 onlyhad a 0.1% growth in diameter and a 0.4% growth in height. Bycomparison, the product of the composition of Comparative Example A hada 2.7% growth in diameter and an 8.2% growth in height.

The only difference in the compositions of Examples 1, 2, and 3 andComparative Example A was the presence of a straight chain saturatedmono-, di-, or tri-carboxylic acid salt. It is thus believed that thestraight chain saturated mono-, di-, or tri-carboxylic acid salt aidedin the dimensional stability of the products of the compositions ofExample 1, Example 2, and Example 3. By controlling the migration ofwater and acting as a donor or acceptor of free water, the straightchain saturated mono-, di-, or tri-carboxylic acid salt may have allowedprocessing and prevented the formed products from swelling when theproducts were subjected to heat as well as controlled the rate ofsolidification of the product within the desired range. Because thecomposition of Comparative Example A did not contain a straight chainsaturated mono-, di-, or tri-carboxylic acid salt, the composition didnot include a mechanism for controlling the movement of water within thesolid product. The composition of Comparative Example A would not besuitable for processing and failed the test for dimensional stability.

The following test method was used to characterize the compositionsproduced in Examples 4, 5, and 6 and Comparative Example B:

Dimensional Stability Test for Cast Products

Approximately 4000 grams batch of the product using a straight chainsaturated mono-, di-, or tri-carboxylic acid salt as part of thesolidification matrix was first poured into a capsule. The diameter ofthe capsule was measured and recorded. The capsule was maintained atroom temperature for one day, held in an oven at a temperature ofapproximately 104° F. for two days, and then returned to roomtemperature. After the capsule returned to room temperature, thediameter of the capsule was measured and recorded. The capsule wasconsidered to exhibit dimensional stability if there was less thanapproximately 2% swelling, or growth.

Examples 4, 5, and 6 and Comparative Example B

Examples 4, 5, and 6 are compositions of the present invention using astraight chain saturated mono-, di-, or tri-carboxylic acid salt as apart of the solidification matrix. In particular, the composition ofExample 4 used sodium citrate dihydrate as part of the solidificationmatrix, the composition of Example 5 used sodium tartrate dihydrate aspart of the solidification matrix, and the composition of Example 6 usedsodium acetate as part of the solidification matrix. Each of thecompositions of Examples 4-6 also included component concentrations (inweight percent) of softened water, aminocarboxylate, sodiumpolyacrylate, sodium hydroxide 50%, sodium carbonate (dense ash),anionic surfactant, and nonionic surfactant, as provided in Table 3. Theliquids (softened water, aminocarboxylate, straight chain saturatedmono-, di-, or tri-carboxylic acid salt, polyacrylate, and sodiumhydroxide 50%) were premixed in order to form a liquid premix and thepowders (sodium carbonate, anionic surfactant, and nonionic surfactant)were premixed in order to form a powder premix. The liquid premix andthe powder premix were then mixed to form the composition, which wassubsequently poured into capsules.

The composition of Comparative Example B was prepared as in Examples 4,5, and 6 except that the composition of Comparative Example B did notcontain a straight chain saturated mono-, di-, or tri-carboxylic acidsalt but did contain the same quantity of available water.

Table 3 provides the component concentrations for the compositions ofExamples 4-6 and Comparative Example B.

TABLE 3 Exam- Exam- Exam- Comp. Component ple 4 ple 5 ple 6 Example BWater, softened, wt. % 32.00 28.03 28.03 28.03 Sodium citrate dihydrate,0.00 4.00 0.00 0.00 wt. % Sodium tartrate dihydrate 4.00 0.00 0.00 0.00Sodium acetate, wt. % 0.00 0.00 4.00 0.00 Aminocarboxylate wt. % 0.003.00 3.00 3.00 Sodium polyacrylate, wt. % 0.75 0.75 0.75 0.75 NaOH, 50%,wt. % 0.33 0.33 0.33 0.33 Sodium carbonate, wt. % 57.92 58.89 58.8962.89 Anionic surfactant, wt. % 1.00 1.00 1.00 1.00 Nonionic surfactant,wt. % 4.00 4.00 4.00 4.00

After the compositions of Example 4-6 and Comparative Example B wereformed, they were subjected to the dimensional stability test for castproducts, as discussed above, to observe the dimensional stability ofthe compositions after heating. The results are tabulated below in Table4.

TABLE 4 Initial Post-heating % Growth Example 4 Diameter, mm 161 163 1.2Example 5 Diameter, mm 160 161 0.6 Example 6 Diameter, mm 160 162 1.2Comparative Example Diameter, mm 162 170 4.9 B

As illustrated in Table 4, the cast products of the compositions ofExample 4-6 exhibited considerably less swelling than the cast productof the composition of Comparative Example B. In particular, the productof the composition of Example 4 experienced only a 1.2% growth indiameter, the product of the composition of Example 5 experienced only a0.6% growth in diameter, and the product of the composition of Example 6experienced only a 1.2% growth in diameter. By comparison, the productof the composition of Comparative Example B had a 4.9% growth indiameter.

The only difference in the compositions of Examples 4-6 and ComparativeExample B was the presence of a straight chain saturated mono-, di-, ortri-carboxylic acid salt. It is thus believed that the straight chainsaturated mono-, di-, or tri-carboxylic acid salt aided in thedimensional stability of the products of the compositions of Examples4-6. By controlling the migration of water and acting as a donor oracceptor of free water, the straight chain saturated mono-, di-, ortri-carboxylic acid salt may have allowed processing and prevented thecast product from swelling when the product was subjected to heat aswell as controlled the rate of solidification of the product within thedesired range. By contrast, because the composition of ComparativeExample B did not contain a straight chain saturated mono-, di-, ortri-carboxylic acid salt, the composition did not contain a mechanismfor controlling the movement of water within the solid product. Thecomposition of Comparative Example B failed the test for dimensionalstability and would not be suitable for manufacture.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. A solidification matrix consisting essentially of: (a) a straightchain saturated carboxylic acid salt selected from the group consistingof: acetic acid, gluconic acid, malic acid, succinic acid, glutaricacid, adipic acid, tartartic acid, and citric acid; (b) sodiumcarbonate; and (c) water; (d) wherein the solidification matrix is ahydrate solid; (e) wherein if heated at a temperature of 120 degreesFahrenheit, the solidification matrix is dimensionally stable and has agrowth exponent of less than 2%; and (f) wherein the solidificationmatrix is phosphorous-free and NTA-free.
 2. The solidification matrix ofclaim 1, wherein the straight chain saturated carboxylic acid saltconstitutes between about 1% and about 15% by weight of thesolidification matrix.
 3. The solidification matrix of claim 1, whereinthe sodium carbonate constitutes between about 20% and about 70% byweight of the solidification matrix.
 4. The solidification matrix ofclaim 1, wherein the water constitutes between about 2% and about 50% byweight of the solidification matrix.
 5. A solid detergent compositioncomprising: (a) between about 1% and about 15% straight chain saturatedmono-, di-, or tri-carboxylic acid salt by weight of the solid detergentcomposition, wherein the salt of the straight chain saturated mono, di-,or tri-carboxylic acid salt is selected from the group consisting of:acetic acid, gluconic acid, malic acid, succinic acid, glutaric acid,adipic acid, tartartic acid, and citric acid; (b) between about 2% andabout 50% water by weight of the solid detergent composition; (c) lessthan about 40% builder by weight of the solid detergent composition; (d)between about 20% and about 70% sodium carbonate by weight of the soliddetergent composition; (e) between about 0.5% and about 10% surfactantby weight of the solid detergent composition; (f) less than about 0.5%phosphorous containing compounds by weight of the solid detergentcomposition; and (g) less than about 0.5% NTA containing compounds byweight of the solid detergent composition; (h) wherein if heated at atemperature of 120 degrees Fahrenheit, the solid detergent compositionis dimensionally stable and has a growth exponent of less than 2%. 6.The solid detergent composition of claim 5, wherein the straight chainsaturated mono-, di-, or tri-carboxylic acid salt constitutes betweenabout 1% and about 10% by weight of the solid detergent composition. 7.The solid detergent composition of claim 5, wherein the waterconstitutes between about 5% and about 40% by weight of the soliddetergent composition.
 8. The solid detergent composition of claim 5,wherein the builder constitutes less than about 30% by weight of thesolid detergent composition.
 9. The solid detergent composition of claim5, wherein the sodium carbonate constitutes between about 45% and about65% by weight of the solid detergent composition.
 10. The soliddetergent composition of claim 5, wherein the surfactant constitutesbetween about 1% and about 5% by weight of the solid detergentcomposition.
 11. A solid block detergent composition comprising: (a)between about 1% and about 15% sodium citrate by weight of the soliddetergent block composition; (b) between about 2% and about 50% water byweight of the solid block detergent composition; (c) less than about 40%builder by weight of the solid detergent block composition; (d) betweenabout 20% and about 70% sodium carbonate by weight of the solid blockdetergent composition; (e) between about 0.5% and about 10% surfactantby weight of the solid block detergent composition; (f) less than about0.5% phosphorous containing compounds by weight of the solid detergentcomposition; and (g) less than about 0.5% NTA containing compounds byweight of the solid detergent composition; (h) wherein if heated at atemperature of 120 degrees Fahrenheit, the solid block detergentcomposition is dimensionally stable and has a growth exponent of lessthan 2%.
 12. A composition consisting essentially of: (a) asolidification matrix comprising a salt of a straight chain saturatedmono-, di-, or tri-carboxylic acid, sodium carbonate, and water, whereinthe straight chain saturated mono-, di-, or tri-carboxylic acid isselected from the group consisting of acetic acid, gluconic acid, malicacid, succinic acid, glutaric acid, adipic acid, tartartic acid, andcitric acid; and (b) at least one functional ingredient; (c) wherein ifheated at a temperature of 120 degrees Fahrenheit, the composition has agrowth exponent of less than 2% and is dimensionally stable; and (d)wherein the composition is substantially free of phosphorous containingcompounds and NTA containing compounds.
 13. The composition of claim 12,wherein the functional ingredient is selected from the group consistingof: chelating agents, sequestering agents, inorganic detergents, organicdetergents, alkaline sources, surfactants, rinse aids, bleaching agents,sanitizers, activators, detergent builders, fillers, defoaming agents,anti-redeposition agents, optical brighteners, dyes, odorants, enzymes,corrosion inhibitors, dispersants, and solubility modifiers.
 14. Thecomposition of claim 12, wherein the salt of the straight chainsaturated mono-, di-, or tri-carboxylic acid constitutes between about1% and about 15% by weight of the solidification matrix.
 15. A method ofsolidifying a composition, the method comprising: (a) adding asolidification matrix to the composition, the solidification matrixconsisting essentially of a straight chain saturated mono-, di-, ortri-carboxylic acid salt, sodium carbonate, and water to form a hydratesolid, wherein the straight chain saturated mono-, di-, ortri-carboxylic acid is selected from the group consisting of aceticacid, gluconic acid, malic acid, succinic acid, glutaric acid, adipicacid, tartartic acid, and citric acid, wherein the composition includesless than about 0.5% phosphorous containing compounds by weight of thecomposition and less than about 0.5% NTA containing compounds by weightof the composition; and (b) solidifying the composition for betweenabout 1 minute and about 3 hours to form a solid composition that, ifsubjected to a temperature of 120 degrees Fahrenheit, is dimensionallystable and has a growth exponent of less than 2%.
 16. The method ofclaim 15, wherein the composition solidifies in between about 1 minuteand about 2 hours.
 17. The method of claim 16, wherein the compositionsolidifies in between about 1 minute and about 20 minutes.
 18. Themethod of claim 15, wherein the straight chain saturated mono-, di-, ortri-carboxylic acid salt constitutes between about 1% and about 15% byweight of the solidification matrix.
 19. The method of claim 15, whereinthe straight chain saturated mono-, di-, or tri-carboxylic acid salt andwater of the solidification matrix are provided as a liquid premix.